I plan to visit San Francisco area for 3 weeks next June. I would like to spend about 10 days travelling around Yosemite in order to see all of it.Is it possible to spend this long travelling around it? I plan on walking and biking as much as I can.I see that most people only spend 2-3 days around it so I'm not sure of my itinerary yet or the best route to travel around it.

Most of Yosemite can be seen by hiking, not driving or biking. There are basically two roads, not counting the one down to Hetch Hetchy. Have a look at a map - you can spend a few days in the Valley and do some day hikes, and ride up to Tioga Pass and spend a night in the backpacker camp for five dollars because you arrived on a bike. Then day hike and enjoy the many sights there. Well worth spending some quality time. That's if it continues as it has been, with low snow in winter - Tioga Pass in a good snow year doesn't open til mid to late June.

Watch the weather reports and current conditions page for Yosemite starting in March and see how it goes.

You have to be a very careful biker. In one day, driving back from Hetch Hetchy, I ran across three places on the narrow two lane winding roads where rangers were stopping traffic and trying to help bikers who went off the road. You will be competing with tourists who aren't used to driving on mountain roads or driving rented RVs. I would recommend getting to a location (the valley, Tuolumne Meadows) and using the local free shuttles once there to get to trailheads or stores or visitor centers.

Harry asked, "Is it possible to spend this long travelling around it?" (10 days)Certainly! One could spend a year there and still have lot's to explore. You might take a look at this page: http://www.nps.gov/yose/planyourvisit/hiking.htm . Just the day hikes linked on that page would take most folks several weeks to hike.